The present invention relates to an automatic accompaniment apparatus, such as an auto-rhythm machine, auto-bass machine, and the like and, more particularly, to an automatic accompaniment apparatus for receiving a plurality of arbitrary tones and generating musical tones in accordance with an accompaniment pattern.
In a known conventional auto-rhythm apparatus, a waveshape of a tone signal input therein through, e.g., a microphone, is stored in a RAM (Random Access Memory), and the input tone waveshape is read out from the RAM in accordance with a rhythm pattern, thereby generating a rhythm tone (e.g., Japanese Utility Model Laid-Open No. 60-145497).
With the conventional apparatus, however, a waveshape for only one tone can be stored in the RAM. Therefore, the rhythm performance becomes monotonous.
In order to provide various rhythm performance modes, a plurality of input tone waveshapes have to be stored. As a method to do it, it can be considered that a plurality of RAMs are arranged, or an address of a single RAM is divided to determine a plurality of memory areas which can be independently accessed, and that, thus, different input tone waveshapes are stored in each RAM or in each memory area.
However, with this arrangement, each RAM or memory area must have a capacity capable of storing a waveshape corresponding to a maximum data volume among input tone waveshapes. Therefore, the total memory capacity of a waveshape memory is increased, and for a waveshape having a small data volume, the corresponding memory space becomes nonusable.